Matrix packing



J. F. SANTO MATRIX PACKING Sept. 18, 1962 Filed June 13, 1958 R. DE mCLC N 5R E ww v 2, m N

R ww 3,054,347 MA PACKING John F. Santo, 1336 Live Oak Drive,Jacksonville, Fla. Filed :lune 13, 1958, Ser. No. 741,933 3 Claims. (Cl.lill-401.2)

This invention relates to a method of packing a printers matrix and to aprinters matrix packing material, and to a novel machine for theapplication of the packing material to the matrix.

In the printing of newspapers and similar linotype printing processes,it has long been the practice to collect type in a suitable chase as aform, to press a moist fibrous material matrix sheet against the type byexerting pressure against the back surface of the sheet, by means ofcompressed air or a rubber pad, thereby to impress the type into thefront face and to cause projections to be formed in the back faceroughly corresponding to the type impressions, the projections beingseparated on the back face by valleys or depressed areas between theprojections, and, usually following partial drying of the molded matrixsheet, to paste strips or rectangular pieces of thick paper or cardboardin the Valleys of the back face. Following such backing of the valleys,the sheet is normally subjected to hot vacuum drying and shrinking and,when completely dry, molten metal is cast by pressure against the frontface of the matrix to form a printing segment or plate.

Various arrangements have been suggested to do away with the manualpasted strip packing steps, including the provision of extra sheets ofthick material on the back of the matrix sheet which are ground away orotherwise thinned to form a matrix sheet having a smooth back face. Matshave also been provided with a sheet of material on the back face whichis soft at the time of making the impression but which may thereafter behardened to` provide a hard coating on the back of the matrix sheetsufcient to support the portions of the sheet between the impressions.It has also been suggested to make the matrix itself of a material whichmay be hardened after the impression has been made. Such earliersuggestions have provided a matrix sheet thicker than those for whichthe casting machines were designed, and the adoption thereof requiresrebuilding or replacement of the casting machine and, usually, of thepresses, or changes in all of the Linotype machines and the typeproduced thereby, because of the excess thickness of the final matrixsheet, or these systems have required so much additional processing asto be uneconomic.

It is an object of this invention to provide a method of packing matrixsheets formed in the usual manner from the usual materials, and toprovide a matrix packing material useful in such process, such that thefinal matrix is of the same thickness as a hand-packed, glued-backingstrip type matrix, whereby the final packed matrix is usable inconnection with existing equipment.

It is a further object of the invention to provide a method and apacking material for packing matrix sheets in a manner such that the naldrying of the matrix sheet, after packing, which shrinks the matrixsheet by approximately one-twentieth of its original width and length,does not adversely affect the packing, but provides a matrix shrunk tothe desired degree with the' packing still properly adhered and properlyeffective to support the non-impressed, portions during subsequentcasting of the printing segment.

The novel features which are believed to be characteristic of thisinvention are set forth with particularity in the appended claims. Theinvention itself, however, both as Yto its organization and method ofoperation, together with further objects and advantages thereof, maybest be 3,054,347 Patented Sept. 18, 1962 understood by reference tothefollowing description taken in connection with the accompanyingdrawings, in which:

FIG. l is a plan view of a portion of the back face of an impressed ormolded matrix sheet;

FIG. 2 is a similar view of the portion of the back face following theapplication thereto of packing material in accord with the invention;and

FG. 3 is a partially broken away and partially schematic viewillustrating generally apparatus useful in the process of this inventionand showing steps of the process.

FIG. 1 shows the back face 5 of a matrix sheet 6 following theimpressing or molding thereof, with raised projections 7, `8 whichcorrespond, roughly, to the depressed type and pictorial impressionswhich have been formed in the hidden front face.

As shown in FIG. 2, according to the invention, matrix packing material9 has been applied to the depressed valleys lil, 11 which exist on theback face between the several projections '7, `8. The surface 14 of thepacking material is substantially iiush with the projections, and it isimportant that the thickness of the matrix is not changed by theapplication of the packing material.

The process for packing the matrix is performed in a manner which may beunderstood with reference to FIG. 3. The matrix sheet 6 into which havebeen pressed the type depressions 16, 17 is laid with its front face 18in contact with a surface plate 20. Heat, such as by means of electriclight bulbs 21 in a reflective hood spaced a few inches above the sheetis applied for a suflicient length of time to warm the back face 5 to atemperature of at least about degrees F. but not higher than about 200degrees F. It has been found that about 30 seconds of exposure of amatrix sheet about 18 by 23 inches in size under a reiiector having six500 Watt bulbs provides appropriate heating of the matrix. Such heatingperforms two functions; it provides a preliminary or partial shrinkagein size of the matrix, and it provides a warm and partially or nearlydry surface to which the packing material readily adheres and on whichit tends rapidly to set or cure. It is not essential to the process,however, that the matrix surface be hot at the time the packing materialis applied, although the desired results are more dit`n`cult to attainif the matrix back face 5 is not almost dry or only very slightly damp.

When the matrix surface 5 has been dried and preferably heatedapproximately, a tubular nozzle element 22 is brought into contactacross the sheet and slowly moved from one end of the sheet to the otherso as to traverse the area to be packed.

The nozzle element 22 is generally cylindrical, but the lower portionthereof which comes in contact with the projections 7, `8 of the matrixis slightly flattened as shown at 23. Approximately centrally of thisflattened portion 23 are a series of openings, such as opening 24, andsatisfactory results may be obtained if these openings are eachapproximately one-sixteenth of an inch in diameter and spacedthree-sixteenth of an inch on centers along the length of the flattenedportion 23. The hollow interior 27 of the nozzle element is suppliedwith the semiliquid packing material as indicated at 25, through aconnecting tube 26 extending to the nozzle from a pressurized reservoiror container 28. The packing material is forced from the container intotube 26 by applying compressed air from a suitable source 29 into end 3@of the container behind a free piston 31 tted into the container andpreventing the air in end 30 from contacting the semi-liquid packingmaterial. The air pressure in the container-is adjusted and controlledby a valve 32, and a pressure gauge 33 is preferably provided to assistthe operator in maintaining appropriate pressure. The pressure isadjusted to be a few or many pounds per square inch suiicient to causethe material to be ejected at the desired rate from the nozzle opening24. 'Ihe viscosity of the material, the size and length of tube 26, thesize of openings 24, and other factors, some of which may be subjectedto periodic variation, determine the precise pressure that is requiredto force the material from the openings.

During movement of the nozzle along the back face of the matrix, packingmaterial issues from each of openings 24 whenever the individual openingis opposite a valley, such as valley 1l. Each hole is closed, however,when it encounters one or another of the projections, such as projection7. As seen in FIG. 3, opening 24 has supplied no packing material onprojection 7 by which it has been closed, but the opening suppliesmaterial into valley 10 as it leaves projection 7, as indicated,substantially filling the valley before opening 24 reaches and is closedby the next projection 34.

The matrix, which has been impressed with the type in the chase while ina wet condition, and having been partially dried and shrunk thereafter,and, while still slightly moist, having been placed on the surface plateand subjected to heating to raise the temperature of the back face toabout 150 degrees F., will have become warped or wavy. A smoothingroller 35 is carried by an arm 36 fixed to the nozzle to roll freelyalong the sheet immediately in advance of the nozzle, thereby to insurethat the front face 18 is in contact with the surface plate for portionsof the sheet at and near the nozzle as it progresses along the sheet.

After the nozzle has completed the traverse, the matrix with the valleysof its back face now filled or packed With the material is permitted toremain under the heating elements 21 for about ten to thirty seconds.The speed of movement of the nozzle along the matrix may be about oneinch per second. 'l'he heating bulbs 2l preferably remain energizedthroughout the operation. Setting or curing `of the packing material ishastened by the use of heat after the material has been applied, andsuch curing, particularly of the exposed surface of the packing isimportant because the packed matrix is now placed in the usual shrinkingand drying machine in which shrinkage of about 4 to 5 percent in plandimensions is completed under hot vacuum conditions. In the usual typeof shrinking and drying machine, the packed matrix is held in placeagainst a curved plate by means of vacuum applied through perforationsin the plate. If the packing material were not cured on the exposedsurface, it would be sucked in and would gum the vacuum perforations ofthe machine.

It is necessary that the material applied to pack the matrix not bedestroyed or made brittle from the elevated temperatures encountered inthe shrinking and drying machine or from the temperatures of 400 to 500degrees F. involved in the casting box in which the printing plate iscast against the matrix. The material must also be capable of strongadherence to the matrix. A material meeting these and other requirementsis prepared by mixing the following ingredients in percentages byweight:

To this mixture is then added an equal Weight of starch, which may beconveniently in the form of wheat flour or corn starch, with sufficientagitation or mixing to form a thick, smooth, gummy, semi-liquid, whichhas Very little or no tendency to pour but which may be forced throughtubes and openings. The constituency of the material may vary from thatgiven above by adding starch in a ratio to the latex mixture of betweenapproximately 40-60 and 60-40. If less than about 40 parts of starch isadded to 60 parts of the latex mixture, the material flows readily butsets or cures less rapidly, whereas, starch added above the ratio of60-40 so thickens the material that it becomes very dificult to forcethrough tubes or small openings and, thus, difficult to apply.

The ferrie oxide is included primarily for its coloring effect, and maybe omitted without adversely affecting the material or it may bereplaced by some other coloring material. Colored material is moreconvenient to use since contrast with the matrix color aids in detectionof any errors in application on the matrix.

The latex rubber constituent of the latex mixture comprisessubstantially 40 parts of solids to 30 parts of water. Thus the latexmixture comprises in total about 41 percent of water. The clay fillerprovides thickening and may be replaced by slightly increased starch inpreparing the final material. I'he zinc oxide hastens curing and isdesirable to reduce the time of heating under lamps 21 prior tointroduction of the packed matrix into the shrinking and drying machine.Alteration of the amount of zinc oxide is permitted, but omission undulyprolongs the curing time, and increasing the amount may result in toorapid curing and clogging of the openings 24 of the spreading nozzle.

The casein component may be reduced or increased by about one-half butadherence of the material to the matrix is adversely affected orspreading is made difficult if less than about 2 or 3 percent or morethan about 7 percent of casein is included.

The percentage of water is not critical, but sufficient Water should beincluded t0 insure that the latex mixture exists as an emulsion, yetexcess water is to be avoided as adding to the drying time. The ammoniumcompounds are emulsifying agents and may be replaced if desired by otherknown emulsifying agents.

The process as described provides packing of all valleys havingdimensions of about three-sixteenths of an inch and greater. lt is notnecessary that very small valleys be packed since the pressure of themolten metal in the casting box, and the holding suction against theback of the matrix, are not sucient to collapse the matrix except inareas where the type or pictorial impressions are widely spaced, leavinglarge white areas therebetween. All such areas as might be collapsed arepacked in accord with the process herein described, whereby the finalplate does not comprise areas raised high enough to print at any portionnot originally impressed into the matrix.

It will be seen that in the present process, one man may take the matrixsheets from the moulding machine, complete the packing and place thepacked matrix sheets in the shrinking and drying machine in a matter ofabout a minute and a half or approximately as fast as the sheets can bemoulded. The process now normally employed in newspaper plants requiresseveral minutes of time by one or two skilled packers using bits ofcardboard which are glued in place, plus additional personnel to deliverthe moulded matrix sheets to the packing stations, to collect the packedsheets for drying and to perform other related steps and functionseliminated by the process herein described.

While only a certain preferred embodiment of this invention has beenshown and described by Way of illustration, many modifications willoccur to those skilled in the art and it is, therefore, desired that itbe understood that it is intended in the appended claims to cover al1such modifications as fall within the true spirit and scope of thisinvention.

What is claimed as new and what it is desired to secure by LettersPatent of the United States is:

l. The method of packing a moulded matrix sheet which comprises applyinginto the valleys of the back face of the matrix sheet prior tocompletion of the drying and shrinking thereof a heat-curable, adherentsemiliquid packing material up to the level of the tops of theprojections on said back face, and heating said sheet and said theretoapplied material in the absence of the moulding form against which saidsheet was moulded to a temperature and for a length of time suicient tocure said material and to complete the shrinking and drying of thesheet.

2. The method of packing a printers matrix sheet which has been mouldedwhile wet against a form to leave an impressed front face and anirregular back face having projections corresponding roughly to thefront face impressions and having valleys between said projections, saidmethod comprising the steps of heating at least said back face of saidsheet to between about 125 and 200 F., placing said sheet front -facedown on a at support, applying into said valleys a heat-curable,adherent semi-liquid packing material substantially to ll said valleysup to approximately the level of said projections, and thereafterheating said sheet in the absence of said form as packed with saidmaterial to shrink and complete the drying of the sheet and to completethe curing of said material.

3. The method of packing a moulded matrix sheet which comprisesapplying, prior to nal hot shrinking of the sheet, into the valleys ofthe back face of the sheet, a thick, heat-curable latex emulsion packingmaterial up to the level of the projections on said back face and,thereafter, heating said sheet and material to complete the shrinking ofthe sheet and to cure the material in the absence of the moulding formagainst which said sheet was moulded.

References Cited in the le of this patent UNITED STATES PATENTS 134,196Crump Dec. 24, 1872 286,821 Hoe Oct. 16, 1883 1,988,094 Stimpson Jan.15, 1935 2,007,566 Ernewein July 9, 1935 2,133,981 Frazier Oct. 25, 19382,337,550 Crosby Dec. 28, 1943 2,405,724 Wilder Aug. 13, 1946 2,492,348Baker Dec. 27, 1949 2,541,297 Sampson et al. Feb. 13, 1951 2,650,206Stock Aug. 25, 1953 2,697,253 Kurft Dec. 21, 1954 2,702,927 Travis Mar.1, 1955 2,718,664 Schweitzer Sept. 27, 1955

